The invention concerns an apparatus and a process for pneumatically conveying powdery substances having a container using at least one filter in pipe systems. The invention also concerns the use of said apparatus and/or said process.
EP-A-0 574 596 describes an installation for pneumatically transshipping cement from ships into silos by means of a so-called lock container comprising a plurality of container segments; disposed in the uppermost container segment is an exhaust air filter while the lowermost container segment tapers in a funnel-like configuration.
The chemical. pharmaceutical and foodstuff industries also involve conveying powdery substances and transporting them in a controlled atmosphere. The known installations for conveying powdery substances of that kind are generally matched in regard to their structure to the product which is to be subsequently conveyed; those installations involve individual fabrications which give rise to high levels of installation costs. A further disadvantage with the known installations is inter alia that the required filters already clog up after a short period of operation. As a consequence of that problem, production of the powdery substances is frequently subjected to disturbances which result in production failures that have an adverse effect on costs. It has not been possible at the present time to overcome those deficiencies.
The operation of introducing powder into reaction vessels or reactors within explosive areas is generally effected manually by way of a lock arrangement or a protective valve as most reactors do not have the container comprising a plurality of container segments; disposed in the uppermost container segment is an exhaust air filter while the lowermost container segment tapers in a funnel-like configuration.
The chemical pharmaceutical and foodstuff industries also involve conveying powdery substances and transporting them in a controlled atmosphere. The known installations for conveying powdery substances of that kind are generally matched in regard to their structure to the product which is to be subsequently conveyed; those installations involve individual fabrications which give rise to high levels of installation costs. A further disadvantage with the known installations is inter alia that the required filters already clog up after a short period of operation. As a consequence of that problem. production of the powdery substances is frequently subjected to disturbances which result in production failures that have an adverse effect on costs. It has not been possible at the present time to overcome those deficiencies.
The operation of introducing powder into reaction vessels or reactors within explosive areas is generally effected manually by way of a lock arrangement or a protective valve as most reactors do not have the necessary space for an adequate loading installation. Such a mode of operation however does not comply with the applicable safety rules for obviating the risk of explosion: if the reactor is inerted, the step of manually introducing powders from the manhole results in atmospheric pressures and eliminates the protective effect of the inert gas. Upon manual introduction of solid material, the inerting effect is eliminated within a short period of time (O2 concentration &gt;8%) and is not restored even after prolonged operational N2-flushing.
Furthermore the dust can result in contamination of the environment; the gas vapours which are developed give rise to the risk of asphyxiation for the operating personnel. The risks of explosion during the conveying procedure are possible in particular when the following factors come together at the same time:
oxidisable powder; PA1 powder/oxygen ratio is within an explosion limit (varies according to the respect product involved); and PA1 formation of an ignition source (electrostatic discharge, flame, hot spot, sparks). PA1 a mobile and compact system; PA1 a simple structure with a cylindrical chamber. for many materials (SS, Haselloy, plastic material. glass); PA1 a very simple cleaning operation; PA1 an economical installation; PA1 no damage to the powder during the conveying operation; PA1 no clinging or adhesion of sticky powders with poor flow properties; PA1 a completely closed-off system; no dust formation; PA1 no oxygen feed possible in closed containers.
In consideration of those aspects the inventor set himself the aim of eliminating the acknowledged disadvantages and permitting inexpensive conveying of powdery substances, including sticky substances. In particular the invention seeks to provide that powdery solids can be introduced into reactors or the like units with an enhanced level of safety. 2 Amended Page
That object is attained by the teaching set forth hereinbelow.